Crime on web all set up -- racketeer's game? (6)
I believe the answer is:
tennis
'racketeer's game?' is the definition.
'tennis' can be an answer for 'game?' (tennis is a kind of game). I'm not sure about the 'racketeer's' bit.
'crime on web all set up' is the wordplay.
'crime' becomes 'sin'.
'on' is a charade indicator (letters next to each other).
'web all' becomes 'net' (synonyms. I am not sure about the 'all' bit.).
'set up' says the letters should be written backwards (in a down clue, letters go up).
'sin'+'net'='sinnet'
'sinnet' back-to-front is 'TENNIS'.
Can you help me to learn more?
(Other definitions for tennis that I've seen before include "event" , "Game for two or four" , "Medieval, originally French, sport, codified by the British" , "Game played with racket and ball" , "Game (where love is nought?)" .)